Many medical procedures require the insertion of a tube-like member, such as a catheter, sheath, or other tube to gain access through tissue and guide other instruments to the procedure site. After completion of the procedure, the tube-like member is removed from the patient generating a tissue tract in its path of withdrawal.
One such medical procedure is a needle biopsy performed more than one-half million times in the United States each year. Typically, access for the biopsy is provided by a guiding cannula (such as an 18-gauge sheath) through which a biopsy needle (such as a 19-gauge cutting needle) is advanced to the tissue biopsy site. The tissue biopsy is harvested and the cutting needle is withdrawn from the guiding cannula. The guiding cannula is maintained at the biopsy site until it is determined whether or not an additional sample is required (resulting in the reinsertion of the needle). If no further sampling is necessary, the guiding cannula is withdrawn. In every needle biopsy, the patient has a propensity to encounter complications due to bleeding at the location where the biopsy was taken and in the tissue tract caused by the removal of the tube-like member. Malignancy of the tissue at the biopsy site may further increase this propensity. See Marc Zins, et al., “US-Guided Percutaneous Liver Biopsy with Plugging of the Needle Tract: A Prospective Study in 72 High-risk Patients,” Radiology, 184:841, 843 (1992). This propensity for bleeding can be minimized by depositing an appropriate hemostatic material that will embolize the biopsy site and tissue tract by stimulating the coagulation of blood after the biopsy needle has been withdrawn. Devices currently available deposit the hemostatic material by attaching a loaded syringe to the tube-like member that is still inside the tissue. Material is injected into the tube-like member with one hand, via the syringe, while the other hand manually withdraws the sheath from the patient.
Guiding cannula provide access to enable biopsies of most organs. Lung biopsies are complicated most often by pneumothorax, or the leaking of air or gas into the membrane lining the lungs, necessitating a chest tube and an extended hospital stay. Thus, it is desirable to prevent pneumothorax by sealing the tissue tract after the biopsy. This has been successfully accomplished by delivering autologous blood clot material prepared from a 4-8 mL aliquot of the patient's blood (which was given time to clot) and 0.5-1.5 mL of supernatant. This material is injected into the tissue tract through the tube-like member as the tube-like member is being removed from the patient. See Erich K. Lang, et al., “Autologous Blood Clot Seal to Prevent Pneumothorax at CT-Guided Lung Biopsy,” Radiology, 216:93, 94 (2000).
There are several hemostatic materials, such as procoagulants or sealants, which have been employed in needle biopsies. While differing in name and percent composition, these materials have a common ability to facilitate the clotting of blood. For example, fibrin sealant, such as that manufactured by Baxter Healthcare Corp., Glendale, Calif., under the name Tisseel®, is composed of fibrinogen and thrombin (1000 U derived from human pooled plasma). Before use, the thrombin must be re-hydrated and suspended in 40 gmol/mL of calcium chloride solution (2-mL vial). The fibrinogen is re-hydrated in a fibrinolysis inhibitor solution of 3000 inactivator units of aprotin. These two solutions are loaded into two identical 2-mL syringes attached via a plastic clip to a common plunger that is connected to the sheath. See Erik K. Paulson, et al., “Use of Fibrin Sealant as a Haemostatic Agent after Liver Biopsy in Swine,” JVIR, 11:905-911 (2000).
A similar example of hemostatic material is fibrin glue, such as that sold under the name Tissucol® by Immuno AG, Vienna, Austria. Tissucol® is a protein-based sealer of human plasma containing 500 IU of thrombin and 0.1 mL 1131 fibrinogen, from CIS Bio International, Gif-Sur-Yvette, France, and 0.2 mL of contrast medium to tract its progression called Omnipaque 300™, from Schering AG, Berlin, Germany. The delivery mechanism of the fibrin glue is similar to that of the other materials. The glue is loaded into a syringe that dispenses the material in aliquots followed by manually removing the tube-like member as the material is being dispersed.
GelFoam® is another hemostatic product, manufactured by Pharmacia & Upjohn of Kalamazoo, Mich. GelFoam® is composed of gelatinous porcine, which is primarily collagen. Prior to use, the GelFoam® is hydrated, cut into a desired size (such as 5×5×20-mm pieces), and placed one by one, into the tip of a 1-mL tuberculin syringe. Contrast medium may then be added to the syringe. GelFoam® is injected into the tube-like member with the help of a fluoroscope. After each piece is delivered, the syringe and the tube-like member are withdrawn approximately 2-cm and another pre-cut piece of GelFoam™ is injected. This process of injection followed by withdrawal is repeated until the tissue tract is sealed. See, Vincent P Chuang, et al., Sheath Needle for Liver Biopsy in High-risk Patients, Radiology, 166:261-262 (1988).
A biopsy is frequently required in order to obtain a sample of a tumor or other malignant tissue from a patient. A concern of the oncologist is the transmission of tumor cells from the biopsy site during the withdrawal of the guiding cannula that provided access into the tumor. This so-called “needle tract seeding” is a complication that may occur in as many as one in every 1000 procedures. In cases such as these, it is desirable to deposit some form of material, perhaps combined with an anticoagulant, throughout the tissue tract to promote clotting and to minimize the potential seeding of cancer cells in nearby tissue.
Regardless of the medical procedure, the delivery mechanisms currently available all operate by injecting the hemostatic material with one hand and manually withdrawing the tube-like member from the patient with the other hand. Existing devices and their required delivery mechanism provide limited accuracy with respect to the amount of material deposited, and limited control and precision with respect to the location of delivery of material in the tissue tract. The need for dosage control is especially acute when the hemostatic material contains thrombin due to the threat of thrombosis.
There is a need to provide an apparatus capable of controllably delivering an accurate amount of hemostatic material precisely along a tissue tract.